All Blacks coach Steve Hansen is anxious about the prospect of being without Ma'a Nonu for the second Bledisloe Cup Test in Auckland, after the powerhouse centre departed the 12-12 draw in Sydney with a shoulder injury midway through the second half.

Hansen said Nonu, 32, was in serious doubt for the return leg at Eden Park. "I'd say we'd be sweating on whether or not he will be right next week."

With veteran Conrad Smith missing the series opener to be with his expectant wife, Hansen had to hastily reshuffle his centres on Friday, bringing in two-Test rookie Malakai Fekitoa to partner Nonu.

The coach said Smith was likely to be available this weekend, but, if Nonu isn't, the All Blacks must bank on another new midfield combination to combat Australia's Adam Ashley-Cooper and Matt Toomua, presuming Wallabies coach Ewen McKenzie retains his reliable duo.

Ryan Crotty, rushed into the squad on the even of the first Test as cover for Smith, will remain with the All Blacks this week. But Hansen will almost certainly start with Smith and Fekitoa if the Hurricanes captain is available.

"I'm sure we'll get Conrad back at some stage this week ... things seem to be progressing OK there," he said.

Blindside flanker Jerome Kaino is also in some doubt with and elbow injury sustained in the opening minute at ANZ Stadium. Kaino will also have scans, while fellow flanker Richie McCaw said he should be fine to back up despite also suffering a shoulder injury in Sydney.

"I just got a good stinger down there early on but we'll see how we come through," the skipper said. "I think we'll be right."